1. Field of the Invention
The present invention relates to a printing apparatus, comprising a cash drawer control function and to a control method therefor, and relates particularly to a printing apparatus capable of controlling the cash drawer irrespective of the status of the printing apparatus. The present invention is therefore particularly effective when used with systems for processing monetary transactions, such as point-of-sale (POS) terminals and electronic cash registers (ECR).
2. Description of the Related Art
In a conventional printing apparatus when continuing the printing operation is inappropriate, such as when the paper supply is depleted, the printer cover is opened, or an error occurs, conventional printing apparatuses typically stop the printer mechanism containing the printing head, and bring the interface to the host computer off-line (a logical non-connection state) to both protect the printing apparatus and the communications data, and assure user safety. Once this off-line state is entered, however, internal control of the printer apparatus stops, and the data already transferred to the printer apparatus is no longer processed. Data is also no longer received by the printer apparatus, and the printer apparatus cannot receive or process any data output thereto or respond to inquiries from the host computer.
The printing apparatus even moves off-line when the form-feed switch is pressed and paper is being advanced, and when the data receiving buffer storing the received data is full (a buffer full state), and it is difficult to distinguish between these off-line states and off-line states in which it is inappropriate to continue printing.
When the printing apparatus goes off-line, the host computer is no longer able to send the print data, and the complete system, POS, ECR, or other, comes to a stop. In such a case, the host computer typically displays a message such as xe2x80x9cprinter problem, please checkxe2x80x9d on the display device, and the user must manually inspect the printing apparatus and correct the problem leading to the off-line state. However, for many general POS and ECR users, determining the problem is often difficult and time-consuming.
On the other hand, control commands stored in the data receiving buffer are interpreted in a first-in-first-out (FIFO, the first commands stored are the first interpreted) order, and the appropriate command process is executed. Control commands that have been processed are deleted from the data receiving buffer. As a result, as control commands are successively input from the host computer, the commands are stored one after the other in the data receiving buffer, and processed in order from the oldest control command stored. This creates a time lag between output of the control command from the host computer and actual execution of the control command by the printing apparatus.
In conventional printing apparatuses handling cut-sheet forms, the printer mechanism and printer head must be stopped to wait for insertion of the cut-sheet form when the host computer selects a cut-sheet form for printing. Because internal control of the printing apparatus stops at this time, the data received from the host computer once the cut-sheet form selection is made is not processed, and there is no response from the printing apparatus, until the cut-sheet form is inserted or a predetermined cut-sheet form insertion waiting period is completed.
As a result, if the user mistakenly selects cut-sheet form printing, the POS/ECR terminal stops processing for the period, thus delaying further processing and causing the customer to wait. When the printing apparatus is reset or the power is turned off and then on again, the data controlling the printing apparatus settings stored in the printing apparatus is lost. This is a significant problem for a printing apparatus used in POS/ECR terminals in financial transaction systems.
Errors generated in the printing apparatus include recoverable errors, such as paper jams in the paper transport path, and non-recoverable errors, such as problems with the power supply voltage from the AC-DC converter and damage to the head temperature detector of the print head. The methods of handling recoverable and non-recoverable errors differ greatly, and it is therefore necessary to distinguish between the two; this is, however, difficult for the average user.
Furthermore, even if the cause of the error is removed in conventional printing apparatuses, it is necessary to reset the printing apparatus or turn the power off and then on again to escape from the error state. Both of these operations also destroy the data stored to that point in the printing apparatus.
To minimize the effects of these problems, the host computer in data processing systems using such conventional printing apparatuses adds a status request command to each line of data instead of batch sending plural lines of data, and uses the response to determine the current status of the printing apparatus. This, however, adds significant overhead to the host computer, and leads to reduced throughput in the data processing system.
As a result of the above, stand-alone type dedicated data processing systems integrating the data entry device, processing device, and printing apparatus are widely used in conventional POS/ECR systems. Systems connecting a host computer with a printing apparatus using a general-purpose interface are not widely used, even though they offer excellent flexibility, due data reliability problems (i.e., security issues). To improve data reliability and simultaneously improve operability (usability), it is desirable to have a data processing system whereby the cause of any stop in printing apparatus operation can be known even while the printing apparatus is in an off-line state, and the cause of the problem can be quickly corrected.
Moreover, conventional POS and ECR systems typically place the cash drawer in which money is held below the printing apparatus, and issue the cash drawer open/close signal from the printing apparatus. So-called terminal printing apparatuses that are connected through some interface to a host device to execute a printing process according to the control commands received from the host device comprise a means for outputting the cash drawer open/close signal for a specified time from the output port of the specified port number. To reduce the standby time to completion of the control commands of the host device, the control commands are temporarily stored to a command buffer, and then read and executed in the order stored (first-in-first-out).
While the command buffer size varies according to the model and application of the printing apparatus, the command buffer is often also used as a print data buffer, and can therefore generally store a large number of control commands. Therefore, when many control commands are stored in the command buffer, significant time may be required to open the cash drawer even though the cash drawer open command has been sent from the host device. More specifically, once a receipt printing or other printing process has been started, monetary transactions such as storing cash received or making customer change must wait until the printing process has completed. As a result, the user must wait for an extended period of time, and numerous problems therefore remain for printing apparatuses used in systems for processing monetary transactions, such as point-of-sale (POS) terminals and electronic cash registers (ECR).
Faster processing is demanded in printing apparatuses for the POS/ECR market in recent years. Because transaction processing in particular requires manual intervention, it is necessary to open the cash drawer immediately as soon as an open request is issued.
Therefore, an object of the present invention is to provide a printing apparatus whereby the above problems can be solved.
It is another object of the present invention to provide a high reliability data processing apparatus.
It is a further object of the present invention to reduce the overhead on the host computer.
It is an additional object of the present invention to provide a user-friendly apparatus.
To achieve the above objects, a printing apparatus according to the present invention comprises: a receiving means for receiving control commands and print data; a storage means for storing at least the control commands; a first control command interpreting means for interpreting the control commands received by the receiving means; a second control command interpreting means for reading and interpreting the control commands stored in the storage means in a first-in-first-out (FIFO) order; and a process execution means for executing the corresponding processes based on the interpreted results output from the first and second control command interpreting means. In this printing apparatus, the process execution means executes the process corresponding to the interpreted result output from the first control command interpreting means with priority over the process corresponding to the interpreted result output from the second control command interpreting means.
The process execution means comprises: a first process execution means for executing the process corresponding to the control command based on the interpreted result output from the first control command interpreting means; and a second process execution means for executing the process corresponding to the control command based on the interpreted result output from the second control command interpreting means; and the first process execution means executes the required process while interrupting the operation of the second process execution means.
To enable the host device to determine the cause of the stop in printing apparatus operation, the printing apparatus of the invention may further comprise: a device-condition detection means for detecting the status of the printing apparatus; a control means for prohibiting or permitting operation of the received-data storage means according to the detection result output from the device-condition detection means; and a transmission means for transmitting data to the host device. In this embodiment, the first process execution means comprises a device-condition reporting means for reporting the data obtained by the device-condition detection means to the transmission means.
To enable the host device to recover from errors in the printing apparatus, the printing apparatus of the invention further comprises an error state flag storage means for storing error state flags set according to the occurrence of error states. The printing apparatus in this case further comprises the second process execution means stopping process execution while the error state flag is set; and the first process execution means comprising an error state flag resetting means for resetting the error state flag.
To further enable the host device to cancel the cut-sheet form insertion waiting state of the printing apparatus, the printing apparatus of the invention further comprises a cut-sheet transport means for transporting and supplying cut-sheet print media to the printing means; a cut-sheet transport control means for waiting until a cut-sheet print medium is supplied to the cut-sheet transport means, and then beginning print medium supply by the cut-sheet transport means; and a cut-sheet transport state detection means for detecting the status of the cut-sheet transport control means. The first process execution means in this case comprises a cut-sheet supply wait-state cancellation means for canceling operation of the cut-sheet transport control means when the cut-sheet supply wait-state of the cut-sheet transport control means is detected by the cut-sheet transport state detection means.
A data processing apparatus according to the invention using a printing apparatus according to the invention comprises a printing apparatus and a host device. The printing apparatus of this data processing apparatus comprises: a transmission apparatus for transmitting data to the host device; a receiving means for receiving said control commands and print data; a storage means for storing at least the control commands; a device-condition detection means for detecting the status of the printing apparatus; a control means for prohibiting or permitting operation of the received-data storage means according to the detection result output from the device-condition detection means; a first control command interpreting means for interpreting the control commands received by the receiving means; a second control command interpreting means for reading and interpreting the control commands stored to the received-data storage means in a first-in-first-out (FIFO) order; a device-condition reporting means for reporting the data obtained by the device-condition detection means to the transmission means based on the interpreted result of the first control command interpreting means; and a normal process execution means for executing the processes corresponding to the control commands based on the interpreted results of the second control command interpreting means.
The device-condition reporting means interrupts operation of the normal process execution means and executes the process.
The host device of this data processing apparatus comprises a storage state detection means for detecting the state of the control means; and a command transmission means for transmitting to the printing apparatus a report device-condition command, the command being a control command requesting transmission of the device condition detection data, and being interpretable by the first control command interpreting means.
By means of the invention thus described, it is possible for the host computer to determine and evaluate the cause of an off-line printing apparatus state even after the printing apparatus goes off-line. The host computer can thus notify the user by means of posting a message, and the system can recover from the off-line state by means of host computer control if the user corrects the cause of the problem. In addition, when the printing apparatus is in a cut-sheet insertion standby state, the waiting state can be canceled by the user issuing a xe2x80x98cancel cut-sheet insertion waiting state commandxe2x80x99 from the host computer.
When an error occurs in the printing apparatus, it is also possible for the host computer to determine what error occurred and where, and whether the error is recoverable or non-recoverable. When the error is recoverable, it is also possible to recover from the error and resume printing once the user corrects the cause of the error. It is also possible to select whether to resume printing from the print line at which the error occurred, or to destroy all data already sent and then recover from the error.
In accordance with another aspect of the present invention, a printing apparatus comprises a data receiving means for receiving command data from a host device, a data storage means for storing the command data received by the data receiving means, and a printer control means for reading the command data stored in the data storage means in a first-in-first-out order and controlling the printing process according to the command data. A command detection means is provided for directly detecting specific command data from the command data received by the data receiving means, and an external device control means is further provided for controlling an external device connected to the printing apparatus according to the predetermined command data detected by the command detection means.
As a result of this configuration, it is therefore possible to independently control an externally connected device as requested by the host device even when command data for the printing process is stored in the data storage means.
To achieve this, it is possible for the external device control means to control the external device parallel to the printer control means controlling the printing process, to control the external device with priority over the printer control means controlling the printing process, or to control the external device according to the end of the printing process when a printing process is being executed by the printer control means.
The process sequence is preferably set appropriately with consideration to the power supply capacity, the processing capacity of the printing apparatus, and other considerations. More specifically, if there is sufficient power supply capacity, simultaneously executing control of both the printing apparatus and external device is preferable with respect to processing speed. On the other hand, temporarily interrupting the printing process and controlling the external device is preferable in applications in which controlling the external device is of higher priority. However, if interrupting the printing process will degrade the print quality, it is preferable to make controlling the external device wait until a break point in the printing process that will not result in degraded print quality, such as at the line end.
Moreover, the external device control means may comprise one or more pulse generating means for generating pulses of which the pulse width is determined according to the predetermined command data. When the external device control means thus comprises pulse generating means, it may further comprise a selection means for selecting one of the two or more pulse generating means according to the predetermined command data.
The external device is more specifically a cash drawer, and the external device control means is a drawer control means for controlling cash drawer opening. The data receiving means preferably receives data from the host device in data units of a known size, the predetermined command data comprises plural data units, and the command detection means comprises a data counter for counting the number of data units, and a comparison means for comparing the data unit received by the data receiving means with a command pattern expressing predetermined command data according to the data counter value.
As a result, the command data received in one-byte units from the host device can be detected and processed as the data is received. It is therefore not necessary to store a specific number of bytes of command data, and the time required for the detection process can be divided into small pieces. Therefore, if either the data receiving means or the command detection means interrupts printing process control by the printer control means to at least either receive data from the host device or detect the predetermined command data, the benefits of distributing the detection process can be obtained.
Other objects and attainments together with a fuller understanding of the invention will become apparent and appreciated by referring to the following description and claims taken in conjunction with the accompanying drawings.